The API documentation for the hasFeatures method of Android's AccountManager has the following to say about which features are supported by each authenticator:
Account features are authenticator-specific string tokens identifying boolean account properties. For example, features are used to tell whether Google accounts have a particular service (such as Google Calendar or Google Talk) enabled. The feature names and their meanings are published somewhere associated with the authenticator in question.
Does anybody have any idea where "somewhere associated with the authenticator in question" actually is for the authenticator used for Google accounts? I would like to know which features are supported.
I still haven't found any official documentation but I have figured out the main use case, that of determining whether a Google account is associated with a specific Google service.
There is a feature for each service and the feature name is of the form service_<service_code_name>. Using this (possibly out-of-date) list of service code names for Google services, we can check for features such as service_lh2 (Picasa), service_groups2 (Google Groups) and service_mail (GMail).
来源：https://stackoverflow.com/questions/7193222/what-features-are-supported-by-androids-google-accounts-authenticator